The objective of the proposed research is to describe and explain the nature of contraceptive use and nonuse among a probability sample of sexually-active unmarried undergraduate students. To this end it is proposed to analyze demographic, attitudinal, and behavioral data so as to determine the socio-cultural and social psychological factors that are of most significance in the decisions young persons make about contraceptive use. The data to be analyzed were collected through a mailed questionnaire survey of 1000 students at a large midwestern university. Alternative explanatory models of the contraceptive behavior of unmarried young persons will be constructed and evaluated through the use of multiple regression techniques and multiple classification analysis.